Alzheimer’s: why too much or not enough sleep increases the risk of developing the disease?

The studies follow each other and resemble each other. The link between poor quality sleep and the risk of developing cognitive disorders seems to be confirmed. Thus, sleeping too little (or too much) would lead to Alzheimer’s disease. After 40 years, the optimal duration of sleep would thus be 7 hours per night.

Sleep and the brain are intimately linked. The first plays an important role in activating the functions of the second and maintaining good psychological health by eliminating waste. But as we age, our habits change, including difficulty falling asleep and staying asleep. These disorders may contribute to cognitive decline in the aging population.

Indeed, each year around the world, nearly 10 million new cases of dementia, such as Alzheimer’s disease, are reported. However, in these patients, sleep is often impaired. Thus, more and more scientific work suggests that the duration of sleep even before the appearance of the first symptoms is likely to contribute to the development of the disease. French researchers have already observed that the risk of dementia is increased by 20 to 40% in people over 50 whose sleep duration is less than or equal to six hours per night.

7 hours per night

But work on the subject continues and even recently, a Sino-British team looked into the question. By examining the data (sleep habits, mental health, etc.) of 500,000 adults aged 38 to 73, the researchers discovered that insufficient sleep durations were associated with impaired cognitive performance, such as the speed of processing a task, visual attention, memory or problem-solving skills. For the authors, one of the possible reasons would be a “disturbance of deep sleep during which memory is consolidated and which would promote the cerebral accumulation of beta-amyloid. “

But the most surprising thing is that they observed the same phenomenon in those who slept excessively! Here the researchers suggest that too much sleep could mean fragmented sleep, and therefore of poor quality.

According to scientists, “7 hours of sleep per night is the optimal amount to maintain good cognitive performance. Finding ways to improve sleep in older adults could therefore be crucial in helping them maintain good mental health and avoid decline. cognitive.”

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